[Question] Can worker in Swarm get address of managers?

[allencloud]

Description

Can a worker in swarm get address of managers in this Swarm cluster?

Currently in a worker node, we can only use docker info to get very few information about this swarm cluster. docker info:

Swarm: active
 NodeID: a49kwjbombpbw9cnz8ajwzh06
 Is Manager: false
 Node Address: 192.168.59.105

While we still can not know which node is manager, or where is the cluster's control entrypoint.

Assuming that we have a large cluster with 10x,100x nodes, but only one manager node. Then if we forget that which one node is manager, actually maybe we lose the control of this swarm node.

If we can get manager address of the cluster from the worker node, it would be a big convenient for users. Since a cluster would have several managers, maybe a leader manager address from every work node is good.

[westsouthnight]

In before I'm ask primary manager from consul, in new swarmkit I don't know how to do this.

[yongtang]

@allencloud @westsouthnight The info.Swarm.RemoteManagers will list the addresses of the managers from the worker node.

[yongtang]

Added a PR #28042 so that Manager Addresses will show up explicitly in the output of docker info:

Containers: 0
 Running: 0
 Paused: 0
 Stopped: 0
Images: 1
Server Version: 1.13.0-dev
Storage Driver: overlay2
 Backing Filesystem: extfs
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins: 
 Volume: local
 Network: bridge host macvlan null overlay
Swarm: active
 NodeID: bu6m8b45fxu8ac4w4wx26iw19
 Is Manager: false
 Node Address: 127.0.0.1
 Manager Addresses: 127.0.0.1:2477
Runtimes: runc
Default Runtime: runc
...

[allencloud]

Great. Thanks a lot. @yongtang